基于分数阶相关盲图像水印算法

针对改进的扩频(Improved spread spectrum,ISS)技术局部嵌入失真不可控制的缺点,结合人类视觉系统模型(HVS模型)建立的限失真的数学模型实现水印自适应最优嵌入.嵌入的水印是一个线性调频信号(LFM),也就是说不同的LFM信号的调频率表示不同的水印信息,检测时采用分数阶相关估计提取水印的调频率.实验结果表明,水印图像在JPEG压缩、各种噪声的攻击下尽管最大的BER接近40%,经过分数阶相关后处理仍然能够实现BER为零的水印信息提取,表现较强的鲁棒性.

A Blind Image Watermarking Algorithm Based on Fractional Correlation

In this paper,an ISS algorithm with adaptive parameters has been proposed.It takes into account the features of human visual system(HVS) and thus can limit the local distortion of the watermarked images.At the same time,it embeds linear chirps as watermark messege.The rates of the chirp represent watermark messege such that each rate corresponds to different messege.By doing this way,the watermarking scheme has better transparency and stronger robustness.Experimental results demonstrate that the proposed algorithm overcomes big local distortion existed in ISS scheme,and is robust enough against many kinds of image processing such as JPEG compression,noise filtering,and we found that the maximum bit error rate to be 40% which is zeros after postprocessing using fractional correlation.